Abstract We demonstrated the applicability of integrated Fibre Bragg Grating (FBG) sensors in the case of flax fabric reinforced epoxy matrix composites produced by resin transfer moulding (RTM). FBG sensors were integrated between the reinforcing layers of the composites. We verified the robustness of FBG-based strain measurement by comparing it to strain gauge strain measurement, optical fine strain measurement and deflection measurement from crosshead displacement during four-point flexural tests. After the extensive characterization of the static properties of the composite material, fatigue tests were performed in the same setup on the specimens with integrated FBG sensors. We demonstrated that with the integrated optical fibres, the cyclic creep strain of the composites could be monitored, which could be used as a criterion to predict the fatigue failure of the composites. The proposed technique can provide an effective and robust way for periodic condition monitoring of composite structures, especially in natural fibre reinforced composites, where creep is more pronounced than in the case of synthetic fibre reinforced composites.

中文翻译：

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使用集成光纤 FBG 传感器对亚麻纤维增强环氧树脂复合材料进行疲劳监测

摘要 我们证明了集成光纤布拉格光栅 (FBG) 传感器在通过树脂传递模塑 (RTM) 生产的亚麻织物增强环氧树脂基复合材料中的适用性。FBG 传感器集成在复合材料的增强层之间。我们通过将基于 FBG 的应变测量与应变片应变测量、光学精细应变测量和四点弯曲测试期间十字头位移的挠度测量进行比较，验证了基于 FBG 的应变测量的稳健性。在对复合材料的静态特性进行广泛表征后，在相同设置中对具有集成 FBG 传感器的试样进行疲劳测试。我们证明了使用集成光纤，可以监测复合材料的循环蠕变应变，可作为预测复合材料疲劳失效的标准。所提出的技术可以为复合结构的定期状态监测提供一种有效且稳健的方法，尤其是在天然纤维增强复合材料中，其中蠕变比合成纤维增强复合材料更明显。